Escapement mechanism



April 10, 1962 P. F. PAGE 3,02

ESCAP EMENT MECHANISM Filed March 28, 1961 INVENTOR PAUL E PA ATTORNEYS3,028,942 ESCAPEMENT MECHANISM Paul F. Page, Newington, Conn, assignorto Royal Mc- Bee Corporation, Port Chester, N.Y., a corporation of NewYork Filed Mar. 23, 1961, Ser. No. 98,847 3 Claims. (Cl. 197-88) Thisinvention relates to an escapement mechanism for business machines andthe like; and more particularly relates to a novel escapement mechanismfor typewriters whereby an automatic repeat letter spacing movement ofthe typewriter carriage is made possible. During normal typingoperations it is often desired to move the carriage through severalletter spacing movements before resuming typing. This is usuallyaccomplished by repeatedly depressing the space bar of the machine. If arelatively large number of depressions are frequently required it willbe apparent that such operations may become time The instant inventionconand control therefor which upon operation normally permits the singlespace movement of the typewriter carriage, but which may be conditionedso as to permit an automatic repetitive operation of the escapementmechanism whereby said carriage may partake of a continuous steppingmovement in a letter feed direction.

()ne object of the instant invention is to provide a very simplereliable arrangement for automatically repeatedly operating theescapement mechanism of a typewriter or the like.

Another object of the invention is to provide a novel self-trippingescapement mechanism which is capable of repeatedly releasing thecarriage for a stepping movement in a letter feed direction in responseto a previous incremental stepping movement of said carriage.

Another object of the invention is to provide a control arrangement fora typewriter escapement mechanism which may be conditioned so that themovement of the teeth of the escapement wheel serves to actuate theescapement control dogs in a manner which permits a continued automaticoperation of the escapement mechanisrn.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings in which like referencenumerals designate like parts throughout the figures thereof andwherein:

FIGURE 1 is a bottom plan view of the principal parts of the instantapparatus.

FIGURE 2 is a top edge view of a portion of the apparatus as shown inFIGURE 1.

FIGURE 3 is a perspective view of the apparatus shown in FIGURE 2.

FIGURE 4 is an active view of the apparatus shown in FIGURE 2.

Referring to FIGURES 1-3 there is shown an escapement mechanism whichcomprises a wheel 11 formed with a plurality of circumferentially spacedteeth 12. Wheel 11 is secured to a shaft 13 which is suitably rotatablysupported in the machine frame and which has mounted thereon a piniongear 14 that meshes with a rack 15 that is fastened to the typewritercarriage 16 in the usual manner. The pinion 14 is connected in any wellknown manner so as to be rotatably fixed in only one rotative directionwith respect to shaft 13. The carriage 16 is biased in a letter feeddirection 17 by means of the usual carriage spring barrel 18. A dogsupporting bail 29 is pivotally mounted on the machine frame 21 3,02,942 Patented Apr. 10, 1 962 ice ' and is provided with a relativelyfixed dog 23. A movable dog 24 is pivotally mounted on the bail 20 bymeans of a pin 25 and is capable of moving through a small are into andout of even registry with the operative abutment surface of the adjacentdog tooth 31. The dog 24 is biased to the non-registering clockwiseposition shown in FIGURE 1 by means of a lever 26 that is pivotallymounted on bail 20 by means of a stud 27 and is biased in a clockwisedirection by means of a spring 30. Teeth 31 and 32 are formed on dogs 23and 24 respectively and when unrestrained the tooth 32 is slightlyoffset from tooth 31 as shown in FIGURE 1. A spring 33 is secured to aprojecting arm 34, FIGURE 4, of the bail 20 so that said bail isnormally biased to a position wherein the movable dog tooth 32 is in itssaid registering position with respect to dog tooth 31 and is inoperative engagement with a tooth 12 of the escapement wheel 11' therebyrestraining the typewriter carriage 16 from incremental movement in theletter feed direction 17. The dog supporting bail Ztlis adapted to beoscillatorily swung through a relatively small are about the pivot axisof studs 22 so that the dog teeth 31 and 32 alternately move into andout of the operative path of movement of the teeth 12 of the escapementwheel 11.

In that the construction and operation of the above described escapementapparatus 'is'similar to that presently being used in the portabletypewriter produced by the Royal McBee Corporation, further detaileddiscussion thereof need not be made here. This conventional typeescapement device is here supplemented as follows.

' A pawl supporting arm, 35, FIGURE 3, is pivotally mounted on themachine frame 21 by means of a pivot pin 36 and is biased in a counterclockwise direction into normal engagement with an ear 37 of a controlor key lever 38 by means of a spring 40. Pivotally mounted on one end ofthe pawl supporting arm 35 is a pawl 41 which is formed at its rightend, as seen in FIGURE 3, with a tooth 42 and at its other end with abent oif tail 43. A projecting stop arm 44 is secured to the frame 21and extends beneath the tail portion of the pawl 41. When the pawlsupporting arm 35 is in its said normal position the pawl 41 is held inan inoperative position, i.e. the pawl tooth 42 lies out of the path ofmovement of the escapement wheel teeth 12 and the limits of anyineffective random pivotal motion of the pawl 41 will be determined bythe side face of the dog 23 and the stop arm 44. Under these conditionsthe escapement mechanism may be cyclically operated in the usual step bystep manner in order to obtain the desired single space movement of thetypewriter carriage in response to the individual depressions of thespace bar.

When an automatic repeat operation of the escapement mechanism isdesired the control lever 38 is displaced so that the lever ear 37swings the pawl supporting arm 35 in a clockwise direction, as viewed inFIGURE 3, towards an operative position. This action will bodily movethe pawl 41 upwardly so that the pawl tooth 42 engages the side face ofthe then adjacent tooth 12 of the escapement wheel. Continued bodilyupward movement of the pawl will thus cause the pawl tall 43 to engageand upwardly displace the dog 23 of the escapement mechanism against theaction of spring 33 as seen in FIGURE 4. This will serve to initiate anescapement cycle and as soon as the escapement wheel 11 starts to rotatein a counter clockwise direction, as viewed in FIG- URE 3, the saidadjacent wheel tooth 12 will swing away and the pawl tooth 42 will befreed for upward movement, as seen in FIGURES 3 and 4, under the actionof the spring 33 which now can swing the bail 20 and the dogs 23 and 2.4in a clockwise direction back to a normal position thus permitting theescapement wheel to partake of the final portion of its incrementalarcuate travel. The execution of this final portion of the incrementalwheel movement however will bring the next tooth 12 into cammingengagement with the pawl tooth 42 so that the pawl is caused to againrotate in a clockwise direction, FIGURE 4, thus automatically initiatinganother cyclic escapement producing movement of dogs 23 and 24 whichafter completion may be followed by a similar initiation of yet anothercyclic operation of the said dogs. As will be apparent as long asthecontrol lever 38 is held in its displaced condition the pawl 41 will bepositioned so as to cause a self-tripping or automatic repeat action inthe operation of the escapement mechanism thus permitting the typewritercarriage to partake of a continuous stepping movement in the letter feeddirection 17. When the pawl 41 is restored to its normal inoperativeposition the escapement mechanism may thereafter be operated in theusual step by step manner. As will be apparent this relatively simpleand inexpensive arrangement for the pawl 41 and its supporting arm 35constitutes an expeditious means for obtaining an automatic repeataction for the letter spacing movements of any spring biased typewritercarriage whether or not the typewriter happens to be a manual or anelectric machine.

While there is in this application specifically described one form whichthe invention may assume in practice, it will be understood that thisform of the same is shown for purposes of illustration only and that theinvention may be modified and embodied in various other forms withoutdeparting from its spirit or the scope of the appended claims.

The invention claimed is:

1. In a typewriter, a frame, a carriage movably mounted on said frame,means for biasing said carriage for movement in a letter feed direction,an escapement mechanism for controlling the incremental steppingmovements of said carriage in said letter feed direction; saidescapement mechanism comprising a toothed member operatively connectedto said carriage, dog means cooperating with said tooth member andmovable so as to permit a single step movement of said carriage in saidletter feed direction, camming means conditionable so as to be operatedby said toothed member and operative thereby, to

move said dog means through an operative displacement,

and means for shifting said camming means from an operative position toan inoperative position.

2. In a typewriter having a frame, a carriage movably mounted on saidframe, spring means for yieldably biasing said carriage in a letter feeddirection, and an escapement mechanism for controlling the incrementalmovement of said carriage in said letter feed direction; said escapementmechanism comprising a toothed escapement wheel operatively geared tosaid carriage, dog means oscillatably mounted on said frame and adaptedto cooperate with the teeth of said escapement wheel so as to permitsaid carriage to move in single steps in said letter feed direction, anda pawl movably mounted on said frame and having a camming portionadapted to cooperate with the teeth of said escapement wheel and anotherportion adapted to engage and operate said dog means, said pawl beingconstructed and arranged for movement between operative and inoperativepositions and when in said operative position and when said dog meansare actuated so that said escapement wheel is permitted to therebyrotate through an incremental distance the resultant cammingdisplacement of the pawl by a Wheel tooth serves to again operate saiddog means so as to permit another operative incremental displacement ofsaid escapement wheel whereby said escapement mechanism is automaticallyrepeatedly operated to permit said carriage to partake of a continuousstepping movement in said letter feed direction.

3. In combination with an escapement mechanism for controlling themovement of a spring biased typewriter carriage having a toothed Wheeloperatively geared to said carriage, and a pair of dogs oscillatablymounted so as to sequentially cooperate with the teeth of saidescapement wheel so as to permit a normal single step movement of saidcarriage; a movable pawl support member, and a pawl pivotally mounted onsaid member, said member being constructed and arranged on the machineframe so as to bodily move said pawl between inoperative and operativepositions, said pawl having a tooth at one end thereof which when saidpawl is moved to said operative position is adapted to camminglycooperate with the teeth of said escapement wheel, said pawl also beingformed with a tail which is adapted to actaute said dogs in response tothe pivotal movement of the operatively positioned pawl caused by thecamming action between the said pawl tooth and the teeth of saidescapement wheel, the pivotal movement of said pawl being timed withrespect to the movement of the other parts of the escapement such thatsaid pawl initiates a new oscillatory cycle of movement of said dogs inresponse to the completion of an increment of movement of saidescapement wheel whereby an automatic repeat actuation of the escapementmechanism continues to occur during the time that said pawl supportmember holds said pawl in its said operative position.

References Cited in the file of this patent UNITED STATES PATENTS937,336 Stickney Oct. 19, 1909

